毛刷电接触对的插拔力研究

针对现有毛刷电接触对插拔力控制方法的缺乏,提出了基于插拔深度控制毛刷电接触对插拔力的方法,在插拔过程中建立毛刷电接触对的结构力学模型和有限元仿真模型,并对毛刷电接触对进行插入力试验.将结构力学模型、有限元仿真模型、插拔力试验所得的插入力随插入深度变化曲线进行对比分析,评估了随机插合等因素对结构力学模型的影响,进行了线簧孔、麻花针和毛刷电接触对在不同插拔深度的插拔力对比试验.结果表明,毛刷电接触对插入力大小与插拔深度成幂函数关系,当典型毛刷电接触对插拔深度为1.8~2.4mm时,插拔力明显较同规格线簧孔、麻花针电接触对的小.基于插拔深度控制插拔力的方法为毛刷电接触对系列化扩展及参数设计提供了一定的参考.     

论结构力学的拓广

随着科学技术，计算和实验手段以及学术思想的日新月异的发展，结构力学的研究范围亦随是到迅速的拓广，出现不少结构力学的分枝，如有限元分析，结构优化设计、结构控制等。西方介绍作者有关结构力学拓广方向的一些观点。     

多约束条件下结构振动系统的容错控制

现代控制理论在工程结构振动领域中的应用性不强,主要是因为其考虑的实际约束条件太少,就该问题进行了研究。首先根据建筑结构力学原理,建立了包含控制输入滞后、执行器故障、参数不确定等的结构系统状态模型。然后基于状态反馈和线性矩阵不等式处理方法给出了一个可满足多约束条件的时滞依赖型鲁棒H∞容错主动控制算法。通过对一个四自由度建筑结构模型在EI Centro地震波作用下振动的主动控制仿真,验证了该方法的可行性,可用于工程结构的振动控制。     

浅析《结构力学》课程的改革

结构力学作为一门技术基础课，与实际的工程问题有着极为广泛的联系。近三十年来，随着计算机技术的发展，结构力学从理论到方法都发生了极为深刻的变化。这一点在结构力学课程的教学中也有所反映。总观其发展趋势，以现代计算机技术为基本分析手段的内容，     

结构力学性能测试仪器的应用状况及发展趋势

介绍结构力学性能测试的应用领域及相关测试仪器的分类及发展历程,分析了当前结构力学性能测试仪器的技术发展趋势,对市场发展前景及行业需求容量进行了预测。     

基于教学设计的结构力学教学的实践

文章就教学设计理论在结构力学教学方面的应用进行了探索与实践，实践表明其对提高结构力学的教学质量和教学效率有着积极的意义。     

京周公路小清河新桥控制爆破拆除

利用桥自身的结构特性,结合结构力学,采用微差控制爆破拆除方案,成功地拆除了小清河新桥,介绍了爆破拆除的设计和施工过程,给出了一些有益的思路和相关的技术参数。     

三维编织复合材料的微结构与力学性能研究进展

综述了国内外近年来对三维编织复合材料细观结构力学模型和力学性能的研究进展.细观结构力学模型研究主要是通过分析三维编织体的拓扑结构建立力学分析模型,主要有"米"字枝状模型、纤维倾斜模型和三细胞模型.对力学性能的研究包括刚度性能和强度性能研究,刚度性能的预测分析方法有解析法、基于均匀化理论的方法和有限元数值仿真;而强度性能的预测大多采用有限元方法来进行.最后,总结了目前研究中存在的问题并对以后的工作进行了展望.     

混合能消元法在受约束非线性控制系统中的应用

本文基于结构力学与最优控制的相似性原理，采用结构力学中的多重子结构法处理受约束非线性控制系统的计算问题。对非线性系统和非线性约束首先进行线性化；进而给出时段的混合能定义；然后根据变分原理，给出时段混合能的消元公式；最后建立起受约束非线性控制系统求解的迭代算法，并给出相应的数值例题。     

高层建筑结构力学分析

目前,高层建筑结构力学分析还是停留在利用现有的计算理论进行被动设计的阶段,不能从根本上满足未来高层建筑朝着技术功能先进和艺术完美相结合的方向发展。因此,对高层建筑的结构力学分析需要实践来改进和发展,并以此促进高层建筑结构的不断完善。本文分析了现代几种高层建筑结构力学的分析方法,包括常微分方程求解器法、有限条法和样条函数法、基于分区广义变分原理与分区混合。     

The optimal control of fracture and stress parameters in a piezoceramic halfspace with cracks

An approach to the determination of the optimal control of fracture and strength parameters in a piezoceramic halfspace with cracks under antiplane deformation conditions is proposed. The distribution over certain part of the halfspace boundary, harmonically changing with time under the influence of axial forces or electric charges is analyzed as a control interaction. The solution of the inverse problem in fracture mechanics is obtained from the solution of the corresponding direct boundary value problem; in this case, the optimization problem is reduced to the momentum problem. The solution of the direct electroelastic problem using the method of the boundary integral equations is obtained. Various control functions permitting to realize the optimal process of control, i.e. the minimal energetic expenses, are given.     

Methods of Optimal Designing of Constructions of Conventional and Composite Materials Subjected to Wave and Static Actions

The problem of optimal designing of inhomogeneous constructions with a combination of properties prescribed in advance is considered. The varied parameters include all the parameters determining the structure of an optimal construction: the physical properties of the layers, the geometric thicknesses of the layers, and the number of layers. An efficient procedure of optimal designing has been developed. The problem of synthesis of the optimal geometry of a stiffened shell with simultaneous search for its optimal structural design has been solved. The mass of the stiffened shell is minimized with allowance for the restrictions of fracture mechanics and static strength and also the restrictions for the stiffness characteristics of the shell in bending and torsion. The method developed and the computational program can be used in designing stiffened shells.     

土体冻融过程中水、热、力三场耦合本构问题及数值分析

根据传热学、渗流理论及冻土力学提出了带相变的温度场、水分场和应力场耦合问题的数学力学模型及其控制方程。利用自行开发的程序进行数值模拟,加入我们推出的本构关系和所建立的数学力学模型,通过对冻土路基水分场、温度场、应力场三场的数值计算结果分析,得到了准确、详尽的符合实际的温度场与应力场、位移场、应变场耦合的计算结果。     

On the convergence of stationary sequences in topology optimization

We consider structural topology optimization problems including unilateral constraints arising from non‐penetration conditions in contact mechanics. The resulting non‐convex non‐smooth problems are instances of mathematical programs with equilibrium constraints (MPEC), or bi‐level programs. Applying nested (implicit programming) algorithms to this class of problems is problematic owing to the singularity of the feasible set. We propose a perturbation strategy combining the relaxation of the equilibrium constraint with the restriction of the design domain to its regular part only. This strategy allows us to attack the problem numerically using standard non‐linear programming algorithms. We rigorously study the optimality conditions for the original singular problem as well as the convergence of stationary points and globally optimal solutions to approximating problems towards respective stationary points and globally optimal solutions to the original problem. A limited numerical benchmarking of the algorithm is performed. Copyright © 2005 John Wiley & Sons, Ltd.     

AN APPLICATION OF THE DISCRETE MAXIMUM PRINCIPLE TO THE SEGMENTATION OF A WALL FOR NONLINEAR SLOPES

A problem consisting of the optimal design of a segmented wall on a surface having a nonlinear slope contour is considered. It is formulated as an optimal control problem and a solution procedure based on the Discrete Maximum Principle is developed. An application to a real case, which previously had been solved by a Dynamic Programming based method, is included together with some critical comments on the above-mentioned technique.     

Optimal design and optimal control of structures undergoing finite rotations and elastic deformations

In this work, we deal with the optimal design and optimal control of structures undergoing large rotations and large elastic deformations. In other words, we show how to find the corresponding initial configuration through optimal design or the corresponding set of multiple load parameters through optimal control, in order to recover a desired deformed configuration or some desirable features of the deformed configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non‐standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures. Copyright © 2004 John Wiley & Sons, Ltd.     

A nonholonomic approach to isoparallel problems and some applications

Isoparallel problems are a class of optimal control problems on principal fibre bundles endowed with a connection and a Riemannian metric on the base space. These problems consist of finding the shortest curve on the base among those with a given parallel transport operator. It has been shown that when the structure group of the principal bundle admits a bi-invariant metric, the normal solutions are precisely the projections of the geodesics (relative to an appropriate Riemannian metric) on the bundle. In this work we obtain a generalization of this result that holds true for any structure group, by transforming the isoparallel problem into a nonholonomic problem of a generalized type. The latter reduces to the geodesic problem if the structure group has a bi-invariant metric. We illustrate the theory with an application to the optimal control of an elastic rolling ball (the plate-ball system), relating some aspects of this problem to the dynamics of a simple pendulum. Finally, we indicate how the study of locomotion of microorganisms can benefit from this approach. This work shows how optimal control and generalized nonholonomic mechanics are related within the context of Lagrangian reduction.     

一种基于最优输出跟踪的多源动态载荷识别方法

基于最优输出跟踪的基本思想,提出了一种时域内多源动态载荷识别的方法。该方法从结构动力响应出发,设计一个最优输出跟踪器并构造性能指标,将载荷识别问题转变为最优输出跟踪问题。通过Adams法求解微分方程,实现了多源动态载荷的识别,并采用L曲线法确定了性能指标中的关键参数。数值算例表明,所述的载荷识别方法能够在响应数据含有噪声的情况下,有效稳定地实现多源动态载荷的重构,具有较强的抗噪能力。     

Laplacian matrices of product graphs: applications in structural mechanics

Graph products have been studied extensively in the recent decade and applied to many problems in structural mechanics, including configuration processing, parallel computing, and optimal analysis of structures. In this paper, a general theorem is proved for the formation of the Laplacian matrices of product graphs. Using this theorem, exact relationships are derived for eigensolution of Laplacian matrices of product graphs. For the cases where no exact formula is available for calculating the eigenvalues of these matrices, some explanations are provided for the approximate approaches. Applications of the Laplacian matrices of product graphs in structural mechanics are illustrated via some examples.